Work-holding attachment for drills.



' 5N0. 846,334. PATENTED MAR. 5, 1907.

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WORK HOLDING ATTACHMENT FOR DRILLS..

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UNITED STATES PATENT OFFICE. I

GEORGE E. MET'OALF, or WORCESTER,TIEFSECHUSETTS, ASSIGNOR To HAR- RINGTON & RICHARDSON ARMS 00., OF WOROESTER, MASSAORUSETTS, A OORPORATION OF MASSACHUSETTS.

Specification of Letters Patent.

Patented March 5, 1907.

Application filed February 11, 1905. Serial No. 245,240.

To aZZ whont it may concern:

Be it known that I, GEORGE E. METOALF, a citizen of the United States, residing at Worcester, in the county of \Norcester and State of Massachusetts, have invented a new and useful WVork-Holding Attachment for Drills,. of which the following is a specification.

This invention relates to that class of clamps or jigs which are employed for holding pieces of work while they are being drilled.

The especial object of this invention is to provide a work-holding attachment or drilling-jig in which a work-holder having a toand-fro or oscillatory motion is used in com bination with a holding-spring and a posi tioning-spring for bringing SUCCGSSlVG pieces of work in position to be drilled.

Further Objects of this invention are to provide a construction with simple adjusting means for the accurate setting and adjustng of the device and to provide a construction in connection with which interchangeable work-holders may be used for the drilling of a variety of different pieces.

To these ends this invention consists of the drilling-jig and of the combinations of parts therein, as hereinafter described, and more particularly pointed out in the claims at the end of this specification.

In the accompanying drawings, Figure 1 is a plan view of a drilling-jig constructed according to this invention. Fig. 2 is a perspective view showing the cooperative relation of the work-holder, the positioningspring, and the holding spring during the drilling of a piece of work. Fig. 3 is a detail view of the operating-piece. Fig. 4 is a detail view ofthe adjustable limit-stop. Fig. 5 is a perspective view showing one particular shape of piece which can be bored or drilled by the aid of a jig constructed according to this invention. Fig. 6 is a detail view of the feed-plate. Fig. 7 is a detail view of the drillrguide. Fig. 8 is a detail view of the preferred form of adjustable bearing of the work-holder, and Fig. 9 is a detail view of a modified form of center adjustment.

In my prior patent, No. 700,964, granted tome May 27, 1902, I-have shown a rotary work-holder which cooperates with a holdingspring and a positioning-spring to clamp sucand in detail, a drilling-jig constructed accord- 5 ing to this invention, as herein illr strated, comprises a plate or srpport T. The table or support T may consist of a flat plate, al though in practice it preferably consists of a box-like casting which is lighter than a solid base or plate.

Mounted on the table or support T is the work-holder 10. The work-holder 10 herein illustrated consists of a sheet-metal plate,

and cooperating with the work-holder 10 to clamp a piece of work TV in place, as shown in Fig. 2, is a holding-spring 11 and a positioning-spring 12. The holding-spring 11 is fastened to the side of a block 13, which is bolted onto the table T by a bolt 14. The positioning-spring 12 is adjustably mounted in a post 16 and is clamped in place by a setscrew 17. VVhe'n the parts are in the position illustrated in Fig. 2, the positioningspring 12 will crowd the piece of work IV toward the farther sides of its socket or recess in the work-holder 10, and the holdingspring 11 will prevent the work-holder from turning while the piece is being drilled by the drill D. Opening from the work-receiving socket of the work-holder 10 is a slot 18 for the end of the positioning-spring.

The drill D is guided during the drilling- Operation by a guide-bushing 19, carried by the guide-piece 20, and the chips and oil are allowed to collect in the pan or guard 21. A feed-plate 22 is fastened in place on the table T by a bolt 23.

Cooperating with shoulders 25 and 26' of the work-holder is a limitstop 24. The

limit-stop 24, as shown most clearly in Fig. 4, is carried by a bolt 27, which is eccentric to the stop 24, and threaded on the bolt 27 is a nut 28. By loosening the nut 28 and turning the limit-stop to various positions the swinging movement of the work-holder 10 can be limited, so that the work-holder will be stopped accurately in position to have the holding-spring and positioning-spring cooperate, as shown in big. 2.

When the parts are in the position shown in Fig. 2, the holding-spring operates like a springlatch engaging behind a shoulder 15 of the workholder to lock the parts in place.

In order to unlock the parts and swing the work-holder around to drop out a completed piece of work and to receive a fresh piece of work, I employ the operating piece 29, which is pivotally mounted on the workholder by means of a screw 30.

Extending up from the operating-piece is a handle 31. The movement of the operatingpiece 29 is limited by pins, and when the operating-piece is pushed in one direction it will release the holding spring 11 and turn the work-holder to the position shown by dotted lines in Fig. 1, and when the operating-piece is used to swing the 'workiolder in the opposite direction it will uncover the shoulder 15 of the work-holder so that the same will be engaged by the holding-spring 11.

To insure the absolute accuracy of position of the pieces of work being drilled, it is sometimes necessary to adjust the center bearing of the work-holder.

As shown in Fig. 8, 34 designates a fixed center post or stud. Fitting on the center post or stud 34 is a sleeve 32, and threaded on the sleeve 32 is a nut 33 for clamping the work-holder 10 between a shoulder and the bottom of the nut.

As shown in Fig. 8, the hole through the work-holder 10, which receives the sleeve 32, is preferably made large enough so that the work-holder may have a considerable range of adjustment with. respect to its center bearing.

In some cases instead of providing the work-holder with an adjustable center bearing I may provide means for adjusting the stud or support on which the work-holder is pivoted. A construction of this kind is shown in Fig. 9, in which the stud or support 37 is arranged eocentrically with respect to the bolt 38, onto which is threaded the clamping-nut 39.

In the use of this construction by loosening the nut 39 the center stud can be turned or adjusted to different positions and then clamped or fastened in place.

In practice I prefer to use the form of center adjustment illustrated in Fig. 8, for the reason that by using a fixed center stud and by adjusting each work-holder with respect to its hearing or journal each individual work-holder will be properly adjusted, so that where a number of interchangeable work-holding plates are employed when said plates have been once properly adjusted with respect to their center bearing the apparatus as a whole can be adapted for the drilling of a variety of different-shaped pieces by simply replacing one work-holding plate with others and without requiring a center adjustment for each change effected, which would be the case when the form of center adjustment illustrated in Fig. 9 is used.

Considering now the operation of-the complete apparatus, when the parts are in the position illustrated in Fig. 2 and the piece of work has been drilled the operating-piece first serves to unlock the holding-spring 11, after which the work-holder is swung to the position illustrated by dotted lines in Fig. 1.. The completed piece of work drops down through its socket in the work-holder, after which the work-holder can be swung back under the feed-plate to receive a new piece of work, which will be carried by the return motion of the work-holder to the operative position illustrated in Fig. 2.

The to-and-fro or oscillatory motion of the work-holder is readily accomplished by the user, and the drilling-jig as a whole is especially adapted for drilling small duplicate parts or pieces-such, for example, as small parts of type-writing machines, sewing-machines, firearms, &c.

I am aware that numerous changes may be made in drilling-jigs constructed according to this invention without departing from the scope thereof as expressed in the claims. I do not wish, therefore, to be limited to the construction I have herein shown and described; but

What I do claim, and desire to secure by Letters Patent of the United States, is

1. In a device of the class described, the combination of a table or support, a stop thereon, and a work-holder mounted to have to-and-fro motion thereon, said work-holder being provided with a pair of stop-shoulders for limiting its motion in both directions and with a work-receiving socket for carrying a piece into position to be drilled when the work-holder is moved in one direction, said socket projecting over the edge of the table to carry the piece of work off from the table support and permit it to be dropped down through the socket in the work-holder when moved in the opposite direction.

2. In a device of the class described, the combination of a table or support, a stop thereon, a work-holder mounted to have toand-fro motion thereon, said work-holder having a p air of stop-shoulders for limiting its motion in two directions, a positioning-spring engaging the work when in operative position, and a holding-spring acting as a stop for the holder during the drilling.

3. In a device of the class described, the combination of a table or support, a work- IIO holder mounted to have to-and-fro motion thereon, a positioning-spring engaging the work carried by the work-holder, a holdingspring acting as a stop during drilling, and an operating-piece for releasing the holdingspring and moving back the work-holder.

4. In a device of the class described, the combination of a table or support, a workholder mounted to have to-andro motion thereon, a positioning-spring, and a holdingspring cooperating with the work-holder, and an adjustable limit-stop to limit the travel of the work-holder.

5. In a device of the class described, the combination of a plate or support, a center stud, a bushing pivoted on the center stud, and a work-holding plate having an opening larger than the bushing and adjustably clamped on the bushing.

6. In a device of the class described, the combination of a table or support, a Workholder mounted thereon and capable of a toand-fro motion, a holdingspring acting as a stop for the work-holder, and an operatingpiece for releasing the holding-spring from the work-holder and moving the work-holder back.

7. A Work-holder capable of a to-and-fro motion and having a pair of stop-shoulders incombination with an adjustable stop 10- cated in the path of both shoulders for limiting the motion of the Work-holder in both directions, and means for automatically locking the work-holder when one shoulder engages the stop.

8. A work-holder capable of a to-andfro motion in combination with means for limiting its motion in two directions, means for automatically locking the holder when in one of its limiting positions, and means for unlocking the holder and moving it in a direction away fiom said limiting position.

9. A work-holder capable of a to-and-fro motion and having a pair of stop-shoulders in combination'with an adjustable stop located in the path of both shoulders for limiting the motion of the work-holder in both directions, means for automatically locking the holder when one of said shoulders engages the stop, and means for unlocking the holder and sending it in a direction to move the lastnamed shoulder away from the stop.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

GEO. E. METCALF.

Witnesses:

PHILIP W. SOUTHGATE, MARY E. REGAN. 

